/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.transforms.windowing;



import com.bff.gaia.unified.sdk.annotations.Experimental;

import com.bff.gaia.unified.sdk.annotations.Internal;

import com.bff.gaia.unified.vendor.guava.com.google.common.base.Joiner;

import org.joda.time.Instant;



import java.util.Arrays;

import java.util.List;



import static com.bff.gaia.unified.vendor.guava.com.google.common.base.Preconditions.checkArgument;



/** A composite {@link Trigger} that fires when all of its sub-triggers are ready. */

@Experimental(Experimental.Kind.TRIGGER)

public class AfterAll extends Trigger.OnceTrigger {



  private AfterAll(List<Trigger> subTriggers) {

    super(subTriggers);

    checkArgument(subTriggers.size() > 1);

  }



  /** Returns an {@code AfterAll} {@code Trigger} with the given subtriggers. */

  public static AfterAll of(OnceTrigger... triggers) {

    return new AfterAll(Arrays.asList(triggers));

  }



  /** Returns an {@code AfterAll} {@code Trigger} with the given subtriggers. */

  public static AfterAll of(List<Trigger> triggers) {

    return new AfterAll(triggers);

  }



  @Internal

  @Override

  public Instant getWatermarkThatGuaranteesFiring(BoundedWindow window) {

    // This trigger will fire after the latest of its sub-triggers.

    Instant deadline = BoundedWindow.TIMESTAMP_MIN_VALUE;

    for (Trigger subTrigger : subTriggers) {

      Instant subDeadline = subTrigger.getWatermarkThatGuaranteesFiring(window);

      if (deadline.isBefore(subDeadline)) {

        deadline = subDeadline;

      }

    }

    return deadline;

  }



  @Override

  protected OnceTrigger getContinuationTrigger(List<Trigger> continuationTriggers) {

    return new AfterAll(continuationTriggers);

  }



  @Override

  public String toString() {

    StringBuilder builder = new StringBuilder("AfterAll.of(");

    Joiner.on(", ").appendTo(builder, subTriggers);

    builder.append(")");



    return builder.toString();

  }

}